Finder.



J. BECKER! FINDER.

APPUCATION FILED DEC- ll. 1916.

Patanted 00$ 1,1915

3 SHEETSSHEET l.

[/-\/\/\| I Inventor LBECKER.

FINDER.

APPUCATION FILED DEC H, 1916.

Patented Oct. 1, 1918.

3 SHEETS-SHEET 2.

J. BECKER.

FINDER. APPLICATION FILED DEC. II. 1916.

3 SHEETS- SHEET 3- Patented Oct. 1, 1918.

1 UNITED STATES PATENT OFFICE.

JOSEPH BECKER, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO EASTMAN KODAK COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

FINDER.

Specification of Letters Patent.

Patented Oct. 1, 1918.

Original application filed February 7, 1905, Serial No. 246,169. Divided and this application filed December To all whom it may concern Be it known that I, JOSEPH BECKER, a citizen of the United States, residing at \Vashington, in the District of Columbia, have invented a new and useful Improve. merit in Finders, of which the following is a specification.

The present application, identified for convenience of reference as Case Aq, isdivision three of my prior application Case J, Serial No. 216169, filed February 17, 1905, now Patent 1,210,136, issued Dec. 26, 1916, and itrelates to certain features of said Case J which are separately patentablc under the head of finders.

My present invention relates to finders of the eccentric lens type, such as described in my Case C, now Patent 1,17 8,47 6; also in my Case Ah division of C, Serial No. 87977, filed March 31, 1916, now Patent 1,210,134, issued Dec. 26, 1916.

The finders illustrated in the drawings of said Case C and said Case Ah, have an image sight located in the incidental part of the finder rays; and they also have a head 25. on the camera, to facilitate the finding of such image sight.

My present invention consists .ina specially simple form of rear sight corresponding to the said bead of my said Cases C and Ah, but ca )ahle of detern'iining the position of the (hiservers eye in altitude as well as in azimuth, by acting in coiiperation with a definite mark on or close by the finder lens.

In a preferred form of myinventiou, the said rear sight consists in a short straight edge located on the rear part of the camera so as to contact transversely with, and projectequally beyond the sides of, one of the four fiat triangular faces which inclose the rectangular pyramid formed by the group of rays proceeding from the finder lens to the observers eye.

The invention is specially convenient as applied to cameras of the type, and to folding cameras that have a front part and a rear part which are held in the same ifiva riable relative position while exposures are being made.

In the accompanying drawings:

Figure 1 is an isometric perspective of a camera of the common box type provided with my improved form of rear-straight- Serial No. 136,293.

edge sight which. here, consists in the horizontal knife edge 15 to 16 of a wedgeshaped recess or chamber built into the top side of the camerabox.

Fig. 2 is a front elevation of the same box camera showing the observers eye at E, and the finder image A of such eye E, just as they appear to a person who is being photographed. 1

Fig. 3 is avertical longitudinal section on plane A E of Fig. 2.

Fig. 4 is another perspective View, such as seen by the operator himself when he uses the camera of Figs. 1 to 3 in photographing an object here supposed to be the letter L.

Fig. 5 is a front elevation of a folding pocket camera of a type which was made and sold in great numbers, prior to 1904, by theEastman Kodak Company, of Rochester, N. Y., and which is here shown provided with a form of my eccentric lens finder that comprises a straight-edge rear sight 115, 116.

Fig. (3 is a side view of the same with:

parts broken away to show the eccentric finder lens, and the rear sight which cooperates with it, both in vertical section.

Fig. 7 is an isometric perspective view of the metallic front part of the same camera, as modified to provide a suitable housing for the finder lens.

Fig. .8 is a similar View showing a modi -fied larger form of lens housing.

Fig. 12 is a vertical section of a modified adjustable form of the invention in which the rear sight is a bead acting on the central finder ray.

- Boa camemt of F 2'98. 1 to 4.

The camera of Figs. 1 to 4 is a camera of the box type specially adapted to present purposes by the provision of a wedge-shaped recess in its upper side, to receive the finder lens in its larger end, and to provide the short horizontal straight edge 15, 16, which is to serve as rear sight in combination with the lower horizontal edge of the finder window, Fig. l, as front sight.

The box 20 contains a fixed partition 21, in which is mounted any, suitable objective The plate or film is represented at 23.

The plate and objective are here both sup-- The groove 24' formed in the bottom wall 24: is of uniform width, but the side grooves. only one of which, 25', appears in the drawing, are tapered and have their inner wall approximately parallel with the camera plate or film 23, to hold the lens according to the rules laid down in my Case A0 or division one of J, now Patent 1,210,137, issued Dec. 26, 1916. Y

A keeper 28, held with screw 29, prevents the lens from falling out and also acts as a guard to protect the lens against injury. and to limit the upper edge of the finder field. The front part of walls 24, 25, 26, is properly flared to admit to the lens all the rays that it is capable of collecting. T heconstruction might be simplified by omitting the flare and increasing the dimensions of the lens to correspond. In this case the side. grooves 25' can be dispensed with and the lens can be held at the proper inclination by the turned down edges of the keeper 29. Such construction is shown in Figs. 10 and 12, which also show other features, but in the construction of Fig, 3 the wedge-shaped housing 24:, 25, 26 is notmade larger than required and the whole of the lens is used. The same general principles apply to either form and will now be described.

The degree of eccentricity and the focal length of the finder lens are here dependent upon the general arrangement, particularly upon the position of the eye and on the extent of the camera field. and I shall now disclose a simple and rapid method for determining these factors. the method being based on the properties of a point A which I call the virtual eye, because it is the position virtually occupied by the operators eye E, in looking through the finder window.

The field of the camera is first plotted by drawing the extreme rays 30. 31, Fig. 3, and is represented by angle a. The field of the finder lens is limited and determined by the finder window or opening 32, 33, and must be equal to 11-, and is plotted by drawing through the lower edge 32 of the finder window a line 30' parallel to line 30: and through the upper edge .33 of the finder window a line 31 parallel to line 31. These lines 30, 31 produced meet in A, which is where the observers eye ought to be if no lens were used. A is the virtual eye before referred to. The observers eye is,-however, situated in E at the point of con-.

f CA on These principles are also applicable when the lens used is compound instead of simple, that is. the focal length and eccentricity found then become the focal length and eccentricity of the compound lens considered as the equivalent of a simple lens.

The central finder ray passes through point M, which, being opposite the center of the outer window mustbe nearer the lower edge of the lens than the upper edge, as clearly apparent in Fig. 3, also in Fig. 2, which shows the centering cross lines marked on the lens.

The inclination of the lens does not either raise or lower the finder image as a whole, and, therefore, the action of such inclined .lens on the rays of light is substantially the same as that explained in the diagram, Fig. 8 of my said Case C.

The central point of the distant camera field. point 0, of Fig. 4, sends, toward the camera three parallel rays. Fig. 3, to wit: (1) a centraleye ray ME; (2) a central finder ray M'C-X which bends at M to proceed to the eye at E; a central camera ray h-["'S.

The observer, therefore, sees the object over the finder along EM. also in the finder along EM. The object, its finder image, and the camera. appear to him as shown in Fig. 4. where the object selected is the letter L to show that the reduced finder image thereof is not only erect, but is also not. turned right to left as it would be in the common convergent lens finder. The advantage of having the finder image. directionally close by the original is that the operator is there by enabled to quickly fix his attention either on the object or on the finder image with out moving either the camera or his own head, just as easilv as can be done by the reader on the drawing in Fig. 4.

means In a folding camera, having relatively fi-Xed plate and lens support, the wedgeshaped recess of Figs. 1 to 4 is no longer necessary, and the invention assumes the tion as applied to a type of folding camera which was made and sold in great numbers, prior to 1904, by'the Eastman Kodak Com: pany, of Rochester, N. Y., and which is in the present embodiment is of the special size required for making a negative whose dimensions are 2%; by 3;; inches.

The camera is well known and need not be described, except in general terms. It comprises a film holding part 100 in which a rolled film is adapted to be unwound for exposure and rewound by means of a key 101.

Within the part l00 is mounted a peculiar system of linkages 102 carrying at its outer end the objective and shutter holding frame 103, 104, which is thus adapted to be" pushed back into a recess of the film holding part 100, or to be easily pulled out into position of use shown in Fig. 0. The front ele- "vation of the camera, Fig. 5, is the same when the camera is folded as when it is opened up; in Fig. 5, however, the camera is supposed to be opened up, and for this reason the operators eye E is also shown reduced within the finder at A, which is identical with point A of Figs. 2 and 3, or with what I have previously called the virtual eye.

The part 103 of the objective holding frame is made of metal and is directly connected with and really forms part of the system of linkages, being guided by it to move 1n and out of part 100 with very nearlyparallel motion. The edges 105 of this part 103 are turned in, to form a recess into which the part 104 is adapted to fit snugly. Parts 104 and 103 are fastened together by means of tWo screws 106. The part 104 has mounted in it the shutter; also the camera objective, whose center is indicated at S.

The part 103, as seen in Fig. 7, is made ust as in the original camera, with-the exception that the upper left-hand corner is modified to form a box-like housing 108, the lower side of which is entirely open. An eccentric lens 127 is trimmed to be easily introduced into housing 108- through this lower open side thereof, and it is firmlv held in place by assembling parts 103 and 101, the

latter being "cut away, as seen in Fig. 6, to accurately close the lower open side of. the lens housing. The lens need not be very firmly held. A little looseness and play,

especially in the thickness, is notobjectionable, and, therefore, a certain roughness of finish is permissible. However, should it be desired to finish roughly and to prevent play,

the camera plate or film 123, to properlv limit and define the finder field so it shall be the same as the camera field. These two openings may be cut so that the rear opening shall apparently be concentric with the front opening for the operator when he has his eye in the proper sighting position.

The line of sight is, however, more easily and preferably determined in accordance with the present invention, that is to say, by forming a rear sight 115, 1-16 on the edge of part 100 and by making the lens of the proper eccentricity as explained in connection with the form of Figs. 1 to 4, so that the pyramid alpha (or), which incloses all the rays that proceed from the findersl27 to the eye at E, shall just rest on the straight .edge 115, 116. This rear sight 115116 is easily formedby cutting a rectangular recess in the vided with two finders, one to be used with I the long edges of the film in horizontal position, the other to be used when the camera is turned so that the long edges are held vertically, and in either case the camera, when used, had to be held at about the height of the waist.

With my improved finder, one finder answers for the two positionsjust men-' tioned, and for any intermediate position, as well. Moreover, the camera in use is held just a little lower than the operators eye,-

that is, just about where it ought to be to show in the camera the same picture as one sees naturally. Cameras adapted to be used waist high, give undesirable perspectives and are diflicult to use in a throng of people.

Camera of Figs. 8 and 9.

On examining Fig. 5, it will beseen that there is ample room at. the right of the finder and below it for a larger finder. A larger form is shown in Figs. 8 and 9. The part referred to by the sign 103' corresponds in every particular with the part 103 of the form just described, but its finder housing 108 is closed below and has, instead, its inside vertical wall left open for the insertion of the finder lens. The part (not shown) corresponding to the block 104 of the first form, is trimmed to close the'lower part of the side opening and block the entrance of the housing so as to lock the finder lens in its home. r

mensions, if need be, to properly hold the same.

Adjustment to cure error in the lens.

In finders with sights such as shown in Fig. 1 of my said Case Ah, no effort need be made to construct the finder lens of any exact degree of eccentricity, because the sights are located in the incidental part of the finder rays.

In arrangements of the type shown in Figs. 3 and 6, however, the finder lens must very nearly have the certain degree of eccentricity needed to cause the rays to proceed from the finder tangentially over the rear sight. If the parts are so proportioned that exact half lenses are required no difiiculty is presented, but'if any other degree of eccentricity is required greater care must be used. Instead of trimming the lens to the certain degree of eccentricity required, it is easier and hence cheaper to make the lens roughly about the required eccentricity and to provide one or more adjustments, either for securing correct eccentricity, or for introducing some compensation of the error that may be present by adjustment of the line of sight. Similar adjustments may also serve to true the lens in the direction perpendicular to its direction of eccentricity. The latter form of correction, for instance, may be applied in the combination of Figs. 5 to 7, by not forming the rear sight notch 115116, Fi 6, until after the lens has been mounted. he camera is then directed onto a distant point which is exactly in the center of the camera field and the eye is set so as to see the same point in the center of the finder field. The rear sight notch -115-116 is then marked and cut, as seen in Fig. 5, if the lens is true. Where the lens is untrue, however, the cut will be shifted to the left or to the right of the position shown in Fig. 5, according to the direction and amount of compensation required.

Camera of Figs. 10 and 11.

In Figs. 10 and 11, I show a form of finder in which all possible errors of the lens are compensated or allowed for by provision of ed to receive the lower thin edge of the lens 227 The lens is ground to fit nicely between the side walls 225 and is held clamped at the proper inclination of the keeper 228, fastened by screws 229, 229.

Any inaccuracies in the degree of eccentricity of the lens, that is, any defect in construction, due to having the thinnest point of the lens a little too high or too low or a little to one side, is easily corrected, as explained later, and, therefore, only ordinary care need be taken in trimming and mountin the lens.

The rear sight 215216 is forme in a strip of metal 202 having a sighting depression 203. This strip canbe slid longitudinally of the camera and transversely thereof into any desired position, and the desired position is readily found as follows:

The camera is mounted on a tripod and is aimed at a distant point so that the image of such point, formed within the camera, shall fall at the center of the plate or film 223; the operator then sets his eye in E so as to see the same distant object centrall inthe finder, and then he shifts strip 202 a ong on the top of the camera to the position where its edge 2152l6 apparently registers with the lower edge 232 of the finder win.- dow. After the strip 202 has thus been set in its desired position, it retains such position by gravity, but it should be fixed against displacement inany preferredmanner. As the correct position of strip 202, Once found, is final and will never again have to be distributed, the strip may be permanently fixed in place by means of screws 205 and 206.

If the thinnest point of the lens happens to be a little out of the median vertical plane, say, at c, Fig. 11, the strip 202 will be found to bear toward the left side of the camera as Camera of 12.

It is noted that the vertical adjustment of the line of sight in the camera of Figs. 10 and 11 is obtained by horizontal adjustment of the rear sight. In Fig. 12 I show a form in which the vertical adjustment of the line of sight is secured by vertical adjustment of the rear sight.

The camera box 320, partition 321, plate 323, floor 324, wall 325, lens 327, and keeper 328 are, respectively, identical with the similarly numbered parts of Figs. 10 and 11. But the rear sight here is a simple pin or screw 310 driven into the flooring 324 of the sighting reces and adapted to act on the central finder my 350, instead ofon the lowest rays 304.- Lateral adjustment is provided for by starting the pin or screw in the proper lateral position; and then, by driving the pin or screw more or less its head can be accurately brought into the path of the central finder ray 350, as seen in the figure.

This constitutes a very simple, accurate, conthe previous figures by a heavily marked arc alpha (0:).

This Fig. 12 camera is claimed specifically in my separate application, Case Ar or division four of J, filed Dec. 12, 1916,Serial NO. 136,428.

What I claim as my invention, anddesire to secure by Letters Patent, is: j

1. The combination with a'camera of the box type having a wedge-shaped recess formed therein,-flaring toward the objective end of the camera, and an eccentric, simple or compound, lens mounted in said recess at its larger end. w

2. The'combination with a camera of the box type having a longitudinal depression formed therein so as to extend throu h the front upright wall thereof; an eccentrlc simple or com ound lens mounted at the for: ward end 0 said depressionfsaid depression being, m'oreover, provided at its rear end with a sight that is situated so as to be grazed by the group of rays that roceeds from the camera field, through the nder, to

.the observers eye.

3. The combination with a camera and an eccentric divergent lens mounted thereon as a finder, of a sight whose location is ,on the camera between the said lens and the position to be occupied by the operators eye,

and means specially adapted to themaking of slight or corrective changes in the said location. I I

4. The combination witha camera, ofan eccentric lens mounted thereon as a finder and an adjustable rear sight adjustable universally in one plane which is so situated as to pass transversely through the pyramid camera of the type comprising: a

alpha (a, Fig. 10) of rays that proceed from the finder to the {observers eye.

5. The combination with a photographlc camera having a finder of the eccentric divergent lens type, of means for determining the position of the observers eye, such means consisting in a short straight edge located on the camera, between the finder and the ob servers eye and so as to contact transversely with one of the four triangular faces of the a correct field when the observers eye is placed at the usual distance from the camera and so as to receive the pyramid of emitted finder rays, grazingly, by such straight edge, anal substantially midway between its two en S.

6. The combination with a photofgraphic orward part adapted to support, more or less directly, the photographic lens; a rear part adapted to receive and support, more or less directly, the sensitized plate or film; and means for holding said two parts in a certain relative position which, in any one of the present difierent camera structures, is the invariable relative position thatthe said two camera parts m'ust have in making exposures; of

an eccentric, simple or compound, divergent lens, mounted in. the said forward part of thecamera; and a cooperatingsi'ght-or mark for said divergent lens, on the said rear part of the camera; all elements being proportioned, arranged, or set and held so that the group of finder rays that proceeds from the camera field, through the finder lens, to the observers eye, shall pass g'razingly over the said sight or mark. x

In testimony whereof, I have signedmy name to this specification.

JOSEPH BECKER. 

